As we have seen, any movement in hand affects the joints in the upper kinetic chain located above the hand. Namely, the elbow & shoulder joint. The muscles surrounding the scapula, clavicle, & humerus work together to create the strength, stability, & flexibility required to balance in our arm balance yoga poses.
The serratus anterior protracts & upwardly rotates the scapula, keeping them pinned down to the rib cage. This engagement aligns the humerus to an optimal position. The latissimus can then help stabilize the shoulder joint. Down dog & many back-bending poses require this same muscle sequencing. In practicing these postures, we are also practicing for the handstand posture.
The deltoids, pectoralis, & rotator cuff muscles help to flex the humerus (so that the arm is overhead) & also stabilize the shoulder joint.
Beyond the hand & shoulders, the muscles of our core (front & back) help us to stabilize our pelvis & spine in order to balance in the inversion. These include but are not limited to the erector spinae, the psoas, & abdominal muscles.
Practicing poses like down dog, ardha uttanasana (while shifting the weight into our hands), bakasana, up-bakasana, jump-throughs, forearm balance & headstand can help us gain familiarity with the process of supporting our body’s weight in our hands.